Expansion joint cover

ABSTRACT

An expansion joint cover ( 10 ) broadly comprises a cover plate ( 38 ) to cover an expansion joint ( 12 ) between a first and second surface ( 14,16 ), an anchor assembly ( 40 ) to secure the plate ( 38 ) to the first surface ( 14 ), an insert ( 46 ) to protect the second surface ( 16 ), and one or more resilient bushings ( 48 ) to isolate the plate ( 38 ) from the anchor assembly ( 40 ). Under adverse conditions, such as during seismic events, the surfaces ( 14,16 ) may move significantly with respect to one another, thereby causing the plate ( 38 ) to slide over the second surface ( 16 ) and the insert ( 46 ) and deform the bushings ( 48 ). Thus, the flexibility of the plate ( 38 ), the durability of the insert ( 46 ), and the resilience of the bushings ( 48 ) all cooperate to allow the cover ( 10 ) to minimize stresses otherwise transferred to the anchor assembly ( 40 ).

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to expansion joints and expansionjoint covers. More particularly, the present invention relates to anexpansion joint cover that can be installed over an expansion jointbetween a first surface and a second surface.

[0003] 2. Description of Prior Art

[0004] Prior art expansion joint covers include cover plates coveringexpansion joints between first and second building surfaces. Typically,a first edge of the plate is coupled to the first surface and an opposedsecond edge is slidably received in a transition recess defined in thesecond surface. The second edge slides in the recess during relativemovement of the surfaces caused by thermal expansion and contraction.

[0005] The second surface typically presents a beveled recess wall wherethe recess meets an adjacent upper surface of the second surface. Duringa seismic event, the joint may narrow such that the second edge of theplate slides over the recess wall onto the upper surface of the secondsurface. The recess wall is therefore subject to spalling, corrosion andpotential impact damage from the second edge of the plate during aseismic event. Additionally, stresses involved with the plate slidingonto the upper surface are typically transferred to bolts anchoring theplate, thereby inducing shock and shear forces capable of damaging thebolts.

[0006] Furthermore, since the plate and the bolts may be constructed ofdissimilar metals, electrolysis may lead to galvanic corrosion of eitherthe plate, the bolts, or both. Additionally, the movement describedabove can be quite noisy.

[0007] Finally, prior art expansion joint systems are typically designedfor installation during building construction. As a result, installationon an existing building as a retrofit can be expensive and laborintensive.

[0008] Accordingly, there is a need for an improved expansion jointcover that overcomes the limitations of the prior art.

SUMMARY OF THE INVENTION

[0009] The present invention overcomes the above-identified problems andprovides a distinct advance in the art of expansion joint covers. Moreparticularly, the present invention relates to an expansion joint coverthat can be installed over an expansion joint between a first surfaceand a second surface. The cover broadly comprises a cover plate to coverthe joint, an anchor assembly to secure the plate, a transition insertto protect the second surface, and one or more bushings to isolate theplate from the anchor assembly. The plate preferably presents a firstedge positioned adjacent the first surface and a second edge positionedadjacent the second surface.

[0010] The anchor assembly preferably includes one or more concreteanchor members each inserted into a hole in the first surface and one ormore bolts each threaded into one of the concrete anchor members. Theinsert protects the second surface from impact damage by the second edgeof the plate during a seismic event.

[0011] Each bushing is preferably made of polyurethane or anotherresilient material, such as cork, rubber, or other flexible elastomer,and comprises a circular face positioned between the plate and the headof one of the bolts and a cylindrical sleeve positioned between theplate and the shank of one of the bolts. The sleeve preferably fitstightly between the shank and one of several penetrations in the plate,thereby securely holding the plate in position relative to the bolts.

[0012] Under normal conditions, such as during thermal expansion andcontraction, the surfaces may move slightly with respect to one another.In this case, the plate slides over the second surface with minimaldeformation of the plate and the bushings. Under adverse conditions,such as during seismic events, the building surfaces may movesignificantly with respect to one another. In this case, the plateslides over the second surface, may flex and slide over the insert, andmay deform the bushings. Thus, the flexibility of the plate, thedurability of the insert, and the resilience of the bushings allcooperate to allow the cover to minimize stresses otherwise transferredto the anchor assembly. Such stresses may otherwise shear the bolts,cause damage to the surfaces, or both.

[0013] Additionally, the bushings accommodate minor misalignment betweenthe bolts and the penetrations in the plate. Such misalignment may occurduring construction of the building, installation of the cover, orduring the cover's service life. Without the bushings, the misalignmentwould otherwise induce stress on the anchor assembly leading to thedamage described above.

[0014] Furthermore, the bushings prevent metal-to-metal contact betweenthe plate and the bolts. Since the plate and the bolts may beconstructed of dissimilar metals, electrolysis may otherwise lead togalvanic corrosion of either the plate, the bolts, or both.Additionally, the bushings minimize any noise associated with themovement described above. Finally, it can be seen that the bushingsabsorb any shock that may be associated with the movement describedabove, thereby reducing any such effects experienced by the anchorassembly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] A preferred embodiment of the present invention is described indetail below with reference to the attached drawing figures, wherein:

[0016]FIG. 1 is a perspective view of an expansion joint cover 10constructed in accordance with a preferred embodiment of the presentinvention and shown covering an expansion joint;

[0017]FIG. 2 is an elevation view of the cover;

[0018]FIG. 3 is a plan view of a bushing of the cover; and

[0019]FIG. 4 is an elevation view of the bushing.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0020] Referring to FIG. 1, an expansion joint cover 10 is shownconstructed in accordance with a preferred embodiment of the presentinvention. The cover 10 is used to cover an expansion joint 12 between afirst building surface 14 and a second building surface 16 of a buildingsuch as a parking garage. Such building surfaces 14, 16 are typicallycomposed of concrete. However, the surfaces 14,16 can have similar ordifferent configurations and textures and may be parallel,perpendicular, or otherwise situated relative to each other.

[0021] Referring also to FIG. 2, the first surface 14 preferablypresents a first upper surface 18 and a mounting recess 20 preferablyhaving a depth of approximately three quarters of an inch adjacent thejoint 12. The mounting recess 20 preferably presents a first supportsurface 22 and a first recess wall 24 between the first upper surface 18and the first support surface 22.

[0022] Similarly, the second surface 16 preferably presents a secondupper surface 28 and a transition recess 30 preferably having a depth ofabout three quarters of an inch adjacent the joint 12. The transitionrecess 30 preferably presents a second support surface 32 and a secondrecess wall 34 between the second upper surface 28 and the secondsupport surface 32. The support surfaces 22,32 are preferablysubstantially aligned, such that they are planar, in order to allow thecover 10 to effectively cover the joint 12.

[0023] Either recess 20,30 may be pre-existing in the correspondingbuilding surfaces 14,16 or may be cut into the building surfaces 14,16,in order to accommodate the cover 10. Alternatively, the cover 10 may beinstalled on the building surfaces 14,16 without either one or both ofthe recesses 20,30. However, this typically requires the cover 10 toprotrude well beyond the building surfaces 14,16, and therefore may notbe desired.

[0024] The cover 10 broadly comprises a cover plate 38 to cover thejoint 12, an anchor assembly 40 to secure the plate 38, a first andsecond support pad 42,44 to support the plate 38, a transition insert 46to protect the second building surface 16, and one or more bushings 48to isolate the plate 38 from the anchor assembly 40. The plate 38 ispreferably composed of approximately three eighths of an inch thick bentaluminum plate to present an approximately one half inch arch forincreased structural strength, as illustrated in FIG. 2. The plate 38extends along the joint's 12 length and is wide enough to span the joint12. Therefore, the plate's 38 length and width are dependent upondimensions of the joint 12. The plate 38 preferably presents a firstedge 50 positioned in the mounting recess 20 and a second edge 52positioned in the transition recess 30. Either edge 50,52 may be beveledin order to avoid presenting sharp corners.

[0025] The anchor assembly 40 preferably includes one or more concreteanchor members 54 each inserted into a hole in the first buildingsurface 14 and one or more bolts 56 each threaded into one of theconcrete anchor members 54. Each concrete anchor member 54 is preferablyconventional and constructed of plastic. Each bolt 56 preferablyincludes a bolt head 58, a threaded end, and a shank 62 therebetween.The head 58 preferably resides external to the plate 38 and holds theplate 38 adjacent the joint 12. The threaded end preferably mates withthe concrete anchor member 45 and holds the bolt 56 in place. The shank62 preferably extends through one of several penetrations in the plate38 adjacent the first edge 50 and through the first pad 42 and thebushing 48.

[0026] Alternatively, the anchor assembly 40 may include one or morebolts 56 cast directly into the concrete making up the first buildingsurface 14. In this case, the anchor assembly 40 may also include a nutthreaded onto each bolt 56 to secure the plate 38 over the joint 12.

[0027] The pads 42,44, are preferably approximately three eighths of aninch thick and preferably composed of a resilient, synthetic material,such as neoprene. The first pad 42 is preferably positioned in themounting recess 20 between the first edge 50 of the plate 38 and thefirst support surface 22 and between the joint 12 and the first recesswall 24. The first pad 42 supports the first edge 50 of the plate 38 andallows the plate 38 to flex and move relative to the first buildingsurface 14.

[0028] Similarly, the second pad 44 is preferably positioned in thetransition recess 30 between the second edge 52 of the plate 38 and thesecond support surface 32 and between the joint 12 and the second recesswall 34. The second pad 44 supports the second edge 52 of the plate 38and allows the second edge 52 to slide thereon during relative movementbetween the building surfaces 14,16.

[0029] The insert 46 is preferably integrally formed of metal, such assteel, aluminum, synthetic resin material, fiberglass, or a compositematerial. Such materials are chosen as needed to withstand expectedloads of a particular installation. The insert 46 is preferablypositioned in the transition recess 30 on the second support surface 32and against the second recess wall 34. The insert 46 is preferablybeveled in order to avoid presenting sharp corners and in order topresent a smooth transition wall 64 between the second support surface32 and the second upper surface 28. In particular, the transition wall64 provides a transition between an upper face 66 of the second pad 44and the second upper surface 28.

[0030] In the preferred embodiment, the transition recess 30 is wideenough so that the second edge 52 remains therein supported by thesecond pad 44 during expected widening and narrowing of the joint 12 dueto thermal expansion and contraction. However, during a seismic event,the building surfaces 14,16 may move toward one another so that thesecond edge 52 slides over the transition wall 64 and onto the secondupper surface 28. During such movement, the transition wall 64 guidesthe second edge 52 between the upper face 66 of the second pad 44 andthe second upper surface 28.

[0031] The insert 46 is preferably constructed of materials less subjectto spalling and corrosion than the concrete making up the second recesswall 34. Because of this, the insert 46 ensures reliable operation ofthe cover 10 for many years. Moreover, the insert 46 protects the secondrecess wall 34 from impact damage by the second edge 52 during a seismicevent.

[0032] Referring also to FIGS. 3 and 4, each bushing 48 is preferablymade of polyurethane or another resilient material, such as cork,rubber, or other flexible elastomer, and comprises a circular face 68positioned between the plate 38 and the head 58 of one of the bolts 56and a cylindrical sleeve 70 positioned between the plate 38 and theshank 62 of one of the bolts 56. The face 68 is preferably approximatelyone and one half inches in diameter and approximately three sixteenthsof an inch thick. The sleeve 70 preferably includes an approximately onehalf inch internal diameter 72 that tightly fits around the shank 62, anapproximately three quarters of an inch external diameter 74 thattightly fits within one of the penetrations in the plate 38, and anapproximately three eighths of an inch length allowing the sleeve 70 tosubstantially completely penetrate the plate 38. Thus, the bushings 48securely hold the plate 38 in position relative to the bolts 56, whichare secured to the first building surface 14.

[0033] Under normal conditions, such as during thermal expansion andcontraction, the building surfaces 14,16 may move slightly with respectto one another. In this case, the plate 38 slides over the second pad 44with minimal deformation of the plate 38, the pads 42,44, and thebushings 48. Under adverse conditions, such as during seismic events,the building surfaces 14,16 may move significantly with respect to oneanother. In this case, the plate 38 slides over the second pad 44, maydeform either of the pads 42,44 and the bushings 48, and may flex andslide over the transition wall 64 of the insert 46. Thus, theflexibility of the plate 38, the resilience of the pads 42,44 and thebushings 48, and the durability of the insert 46 all cooperate to allowthe cover 10 to minimize stresses otherwise transferred to the anchorassembly 40. Such stresses may otherwise shear the bolts 56, causedamage to the building surfaces 14,16, or both.

[0034] Additionally, the bushings 48 accommodate minor misalignmentbetween the bolts 56 and the penetrations in the plate 38. Suchmisalignment may occur during construction of the building, installationof the cover 10, or during the cover's 10 service life. Without thebushings 48, the misalignment would otherwise induce stress on theanchor assembly 40 leading to the damage described above.

[0035] Furthermore, the bushings 48 prevent metal-to-metal contactbetween the plate 38 and the bolts 56. Since the plate 38 and the bolts56 maybe constructed of dissimilar metals, electrolysis may otherwiselead to galvanic corrosion of either the plate 38, the bolts 56, orboth. Additionally, the bushings 48 minimize any noise associated withthe movement described above. Finally, it can be seen that the bushings48 absorb any shock that may be associated with the movement describedabove, thereby reducing any such effects experienced by the anchorassembly 40.

[0036] While the present invention has been described above, it isunderstood that other materials and/or dimensions can be substituted.For example, the face 68 of the bushings 48 maybe between one inch andtwo inches in diameter, and between one sixteenth of an inch and onehalf inch thick; but, are preferably sized to be wider than the head 58of the bolts 56. The bushings 48 may resemble a grommet and comprise twofaces 68 each disposed at opposing ends of the sleeve 70. In this case,the faces 68 may have diameters that differ from one another.Additionally, the internal diameter 72 of the sleeve 70 may be betweenone quarter inch and three quarter inches; but, is largely dependentupon the diameter of the shank 62 of the bolts 56. Furthermore, theexternal diameter 74 of the sleeve 70 maybe between one half inch andone inch; but, is largely dependent upon the diameter of thepenetrations in the plate 38. Finally, the length of the sleeve 70 maybe between one quarter inch and one half inch; but, is largely dependentupon the thickness of the plate 38. In this manner, the dimensions ofthe bushings 48 may be chosen to accommodate the dimensions of the plate38 and the bolts 56. These and other minor modifications are within thescope of the present invention.

Having thus described a preferred embodiment of the invention, what isclaimed as new and desired to be protected by Letters Patent includesthe following:
 1. An expansion joint cover operable to cover anexpansion joint between a first surface and a second surface, the covercomprising: a cover plate operable to span the joint; an anchor operableto penetrate the plate, thereby securing the plate to the first surface;and a bushing between and operable to physically isolate the plate andthe anchor.
 2. The cover as set forth in claim 1, wherein the bushing isresilient and thereby further operable to allow the plate to move withrespect to the anchor allowing the cover to accommodate movement betweenthe surfaces.
 3. The cover as set forth in claim 1, wherein the anchoris secured directly into the first surface.
 4. The cover as set forth inclaim 1, wherein the anchor includes a concrete anchor member disposedwithin a hole in the first surface and a fastener threaded into theconcrete anchor member.
 5. The cover as set forth in claim 1, whereinthe bushing includes a circular face and a cylindrical sleeve.
 6. Thecover as set forth in claim 5, wherein the face is approximately one andone half inches in diameter and approximately three sixteenths of aninch thick.
 7. The cover as set forth in claim 5, wherein the sleeve hasan approximately one half inch internal diameter that tightly fitsaround at least a portion of the anchor.
 8. The cover as set forth inclaim 5, wherein the 1 sleeve has an approximately three quarters of aninch external diameter that tightly fits within a penetration in theplate.
 9. The cover as set forth in claim 5, wherein the sleeve has anapproximately three eighths of an inch length allowing the sleeve tosubstantially completely penetrate the plate.
 10. An expansion jointcover operable to cover an expansion joint between a first surface and asecond surface, the cover comprising: a cover plate operable to span thejoint; an anchor secured directly into the first surface and operable topenetrate the plate, thereby securing the plate to the first surface;and a resilient bushing between and operable to physically isolate theplate and the anchor, thereby operable to allow the plate to move withrespect to the anchor allowing the cover to accommodate movement betweenthe surfaces.
 11. The cover as set forth in claim 10, wherein the anchorincludes a concrete anchor member disposed within a hole in the firstsurface and a fastener threaded into the concrete anchor member.
 12. Thecover as set forth in claim 10, wherein the bushing includes a circularface and a cylindrical sleeve.
 13. The cover as set forth in claim 12,wherein the face is approximately one and one half inches in diameterand approximately three sixteenths of an inch thick.
 14. The cover asset forth in claim 12, wherein the sleeve has an approximately one halfinch internal diameter that tightly fits around at least a portion ofthe anchor.
 15. The cover as set forth in claim 12, wherein the sleevehas an approximately three quarters of an inch external diameter thattightly fits within a penetration in the plate.
 16. The cover as setforth in claim 12, wherein the sleeve has an approximately three eighthsof an inch length allowing the sleeve to substantially completelypenetrate the plate.
 17. An expansion joint cover operable to cover anexpansion joint between a first surface and a second surface, the covercomprising: a cover plate operable to span the joint; an anchor assemblyincluding a concrete anchor member disposed within a hole in the firstsurface, and a fastener threaded into the concrete anchor member andoperable to penetrate the plate, thereby securing the plate to the firstsurface; and a flexible bushing between and operable to physicallyisolate the plate and the anchor, the bushing including a circular faceapproximately one and one half inches in diameter and approximatelythree sixteenths of an inch thick, and a cylindrical sleeve with anapproximately one half inch internal diameter that tightly fits aroundthe fastener, an approximately three quarter inch external diameter thattightly fits within a penetration in the plate, and an approximatelythree eighths of an inch length allowing the sleeve to substantiallycompletely penetrate the plate.